Rotary cutter



y 1, 1940. F. P. MILLER 2,201,495

ROTARY CUTTER Filed Nov. 16, 1937 2 Sheets-Sheet 1 FRANK MILLER I J /Z- May 21, 1940. F. P. MILLER ROTARY CUTTER Filed Nov. 16. 1937 2 Sheets-Sheet 2 IRAN/(R MILLER awmwg Patented May 21, 1940 UNITED sr'iss ROTARY CUTTER.

Frank P. Miller, Meadville, Pa. Application-November 16, 1937, Serial No. 174,879

6 Claims. (CI. 77-56) This invention relates to rotary cutters of the Figure 12 is a section on the line l2l2 of ram FFICE boring bar type, and is an improvement upon the u e invention disclosed in my pri r U it d state In the embodiment of the invention as herein Patent No. 2,021,668 of Nov. 19, 1935. disclosed the cutter comprises a boring bar l4 5 A primary object of the present invention is to Provided W diamefllical $1017 55 Which 5 provide an improved cutter block centering means CeiVeS Cutter hleek Carry the blades including a block engaging centering key and H and Which is backed by a t ust rece v cutter block having contacting or hearing surmember A spring detent 9 ma y h ds faces curved in arcs that are mutually perpenthe thrust member is against movement 10 dicular, so arranged as to insure firm line conmetrically 0f 1the bar but Permits of its dislodg- 10 tact between the block and key in a plane submeht Wheh force is applied from One S Of th stantially parallel to and midway between the 5101?, 50 that the thrust. member y e ov d faces of th tt r m k to permit ready removal and replacement of the A th object i t provide an improved cutter block without disturbing the adjustment I5 t ti of centering key having anghd faces of the centering key. The location of the cutter easily machined for accurate seated engagement block, its Slot, t thrust member and the Spring in a locating socket of the boring bar, to anchor defiant, e shown and described in my aforethe key against rotation on its axis and to dispose 5am Patentthe axis oi the key in direct intersection with AS n in Figures 2 a d e cutter block the axis of th b i b and perpendicular slot H5 at 1ts forward end intersects aperpendicu- 20 the t lar bore 28 which extends entirely through the Other objects will be readily apparent to those boring bar wiffih its axis intersecting the axis skilled in th an; of the bar. Figure 4 shows that the bore 26 is In t acwmpanying drawings which f a of substantially square cross section arranged part of this application and in which like .charwith one 9 Its dlagonals colhclient the am 25 Eaters of referen e are employed to designate of the boring bar. The bore is internally threadlike parts thro h t t severed views; ed adjacent one end, the threaded portion being Figure 1 is a fragmentary elevation of a rotary of clrculal" C3055 i cutter as constructed in accordance with the in- T hOre recfilves the Cehtermg ey 2! 30 vention, parts of the boring bar being shown in Whlch, t Seen In Flgule s a Squared Inner 30 section. end portion 22 and a squared outer end portion Figure 2 i an i l ti through t bar 22' machinedior a snug fitting engagement in on the line 2--2 of Figure 1, parts being in 1 the bore. Between the ends of the key its shank, vation throughout approximately one half of its face Figure 3 is a section taken on line 3-3 of Figarea, fl Ofi O the Outer end to the 35 ure 2. inner end portion, thus forming an inner bearing Figure 4 i a e ti t k on t line 4 4 of face portion- 23 of approximately semi-circular Figure 2. 1 cross-section from the squared outer end of the Figure 5 is a somewhat enlarged axial section F to its Squared h 190N104! 23 40 taken through the outer end portion of the-cutis curved 0h e 23 which 15 h e 40 ter, substantially as in Figure 2, a portion of the throughout,v the axis of the u v p r i n bein centering key being i elevation, angled with respect to the axis of the key. The

Figure 6 is an elevation of a cutter block formother half of the key is formed with flat angled ing a part of the invention. faces from end to end, as at 24 and 25, which 5 Figure '7 is an end elevation of the block shown fit snugly in the forward half of the bore and in Figure 6. together with the squared end portions 22 and Figure 8 is a group perspective view of the cen- 22 prevent rotation of the key on its axis. tering key employed. At its outer end the centering key 2i has swiv- Figure 9 is a fragmentary perspective view elled thereon an adjusting nut 26 in the form of the cutter block edge as formed to engage the of an externally. threaded sleeve engaged in the 50 centering key. threaded portion of the bore 2!). The nut is se- Figure 10 is a section through the cutter block cured on the key by means of a swivel pin 2? taken on the line lfil0 of Figure 6. seated in an axial key socket 238 and anchored Figure 11 is a section on the line Iii-4 l of in the usual manner by means of an anchor pin Figure 5. 29. 'I'he'nut is formed on its inner face por- 55 tion for operative engagement with an appropriate tool.

The cutter block I 6 has its forward straight edge recessed as at 30 to take over the shank of the centering key with sufiicient clearance to permit floating of the block when work re quirements demand a floating mount. The re cess is bisected by the center line of the block.

A feature of the present invention resides in the fact that the inner Wall of the recess 30 is formed with an additional arcuate, segmental shallow recess 3! extending through the block [6 from face to face thereof. As best seen in Figures '7 and 10, the block edge throughout the extent of the recess 3| is curved from face to face of the block, substantially in a curve whereof the axis is in a plane perpendicular to the axis of the portion 23 of the centering key.

In assembling the tool, the cutter block is positioned with its arcuate recess 3| engaging the curved shank portion 23 of the centering key, and as the adjusting nut 26 is advanced the key moves inwardly in the bore 20, the taper of the portion 23 causing the block to be wedged tightly against the thrust member l8. At the same time, due to the surface curvature of both the key portion 23 and the face of the recess 3|, there will result a full bearing contact between block and centering key over the entire extent of the recess 3| along a line substantially midway between the block faces. The curve of the block edge along the recess 3! assures such line contact for, in effect, the material of the block is relieved away from the shank of the key to clear the tapered surface.

A further important feature of this invention resides in the facility with which the centering key may be adjusted to bring the cutter block accurately into dead center relative to the axis of the boring bar in order to overcome inaccuracy in production. The key 2| is centered by removing the required amount of metal from either of the fiat faces 24 or 25, a simple operation and one that requires no highly accurate mathematical calculations. This method of adjustment is highly advantageous in overcoming slight inaccuracies that may be experienced in producing the assembled tool, and in case the bar should be sprung out of line for any reason. The key once adjusted may be maintained at the same adjustment without further regulation, and the cutter block may be removed and replaced without disturbing the set of either the blades or the centering key.

In assembling the cutter, where floating action of the cutter block is desired, the nut 26 is retracted to move the centering key outwardly in the bore 20. The incline of the portion 23 gives a clearance with respect to the block edge recess 3| which permits floating of the block.

When the nut 26 is advanced the centering key 2| moves inwardly in its bore to engage the face portion 23 with the wall of the recess 3|, clamping the block against movement relative to the boring bar. As the arcs of curvature of the key portion 23 and the wall of recess 3| are mutually perpendicular, the bearing contact occurs always as a line contact from side to side of the recess 3| and irrespective of any slight inaccuracy in the theoretically perpendicular relationship of the axis of the centering key relative to the plane of the cutter block.

Contiguous to each blade the body of block I6 is provided from one face to the other with a cylindrical bore receiving locking screw member 31 provided with a tool engageable socket 38.

At their inner ends the blades H are engaged by thrust screws 40, as in my prior Patent No. 2,076,663 of April 13, 1937.

Having thus described the invention, what is claimed is:

1. In a cutting tool, a support having a slot, a cutter block in said slot, a centering key in said support and movable transversely of the block. and one edge of said block and a portion of said key having contacting bearing surfaces curved on arcs that are mutually perpendicular at all points of contact.

2. A centering key for rotary cutters, comprising a shank having a portion substantially square in cross section at each end, said shank also having an intermediate longitudinal portion thereof having a face curved as the segment of a cylinder whereof the axis is inclined relative to the key axis.

3. A rotary cutter comprising a boring bar having an axial slot diametrically disposed therein, a cutter block in said slot, a centering key positioning bore of substantially square cross section extending through said boring bar and intersecting the axis thereof perpendicular thereto, said slot opening at its forward end into said bore, the forward edge of said block having at its center a segmental recess having its wall curved to project into the centering key bore, a centering key adjustable in said bore transversely of said block, said key having flat longitudinal faces contacting the bore walls to prevent rotation of the key on its axis, said key having also a curved face portion adapted to bear against the curved wall of said cutter block recess, the curvature of the cutter block recess wall being in conformity to the curvature of the face portion of the key from end to end of the recess, and said curved face portion of the key being inclined longitudinally of the key relative to its axis.

4. A rotary cutter comprising a boring bar having an axial slot diametrically disposed therein, a cutter block in said slot, said boring bar having a bore substantially square in cross section extending therethr'ough and intersecting the axis thereof perpendicular thereto, said cutter block extending part way across the bore at one edge and having an edge recess of segmental form coaxial with the bore axis, a centering key in said bore and adjustable along its axis transversely of the cutter block and through its segmental recess, said key having a pair of plane longitudinal faces convergent in the axis of the bar at a point opposite the segmental recess of the cutter block and contacting the bore walls to prevent rotation of the key on its axis, said key also having a longitudinally extending face portion curved throughout in an arc whose axis is inclined relative to the axis of the key, the curved face extending uninterruptedly around substantially half the perimeter of the key, the wall of said cutter block recess being curved circumferentially of the key in conformity thereto throughout and also being curved throughout from face to face of the cutter block in an are which is, at any point along the length of the recess, perpendicular to the arc of curvature of the key.

5. In a rotary cutter comprising a boring bar slotted axially and mounting in the slot a cutter block, a centering key in the bar and non-rotatively mounted therein for movement on the axis of the key, the axes of said bar and key intersecting at right angles, said key having a longitudinal face portion curved transversely and bearing against the cutter block, said cutter block having a recess receiving the face portion of the keyand curved in conformity thereto, and said cutter block recess also being curved from one face of the block to the other throughout the length of the recess.

6. In a rotary cutter comprising a boring bar slotted axially and mounting in the slot a cutter block, a centering key non-rotatively mounted in the bar and movable therein on the axis of the key, the axes of said bar and key being perpendicular, said key having a longitudinally extending portion thereof curved transversely on an axis inclined with respect to the axis of the key and bearing against the cutter block, said cutter block having in one edge a segmental recess receiving the curved portion of the key and curved in conformity thereto circumferentially of the key, and the wall of said recess being bowed radially toward the key in an are which is perpendicular to the arc of curvature of the key at any point from end to end of the recess.

FRANK P. MILLER. 

